Pretty much any combination of 700ish motor and b pipe with stock 38mm carbs is going to be within a jet size of stock, nobody on the internet is going to be able to tell you what your jetting should be more accurately than within a jet size, you have to go out on the water and ride your ski, twist the screws on your carbs and see what it does, use that to determine which way to change the jets, take your carbs apart, change the jet, see what it does.
Going from an unmodified B pipe to a bored and port matched B pipe with no other change to the rest of the setup is a really small change, you'll have to be pretty damn good at jetting to be able to tell a difference needed in the carb tuning if there is any difference at all.